This invention relates to a coupler for connecting two sections of a ground vehicle which may have relative articulation and more particularly to such a coupler that also provides for the rapid connection of the power transmission shaft. The coupler of this invention is particularly suitable for ground vehicles that include a first or power and control section that can be connected to a load carrying or ground working section. A ground vehicle on which this coupler can be used is shown in co-pending U.S. patent application Ser. No. 318,540, filed Dec. 26, 1972, now U.S. Pat. No. 3,831,693 issued Aug. 27, 1974, entitled "Steerable Articulation Joint". This co-pending application is assigned to the same assignee. The first or power and control section normally includes, in addition to a prime mover, an operator's station and electrical and hydraulic control systems for controlling the vehicle and may include means for transmitting power to the second section. The second or load carrying or ground working section can take any desired form, such as a container for hauling material, a loader, a dozer, a scraper, a grader, etc. Because the first or power and control section includes a greater number of complex moving parts then the second member, the first section is more expensive to build and to maintain. Also, a common standardized power section which mates with a variety of work sections results in simplified maintenance, repair and training of personnel as well as reducing the required investment in vehicles. Accordingly, a readily engagable and disengagable coupler is provided by the present invention which enables two or more different load carrying or ground working sections to be interchangeable with a given power and control section. This readily attachable and detachable coupler also expedites disconnection of the power and control section as may be needed to expedite maintenance and repair.
Because the apparatus for coupling the two sections may afford articulation between the two sections, the wheels of both sections maintain power driving contact with the ground at all times. This allows the articulated vehicle to maneuver and maintain traction on extremely rugged and irregular terrain and particularly in soft soils. Relative movement between the two sections is afforded along a roll axis (a horizontal axis extending longitudinally of the vehicle) and a yaw axis (a vertical axis through the midpoint of the vehicle) but not in the pitch axis (a horizontal axis extending transversely of the vehicle). The articulation feature may be omitted or locked out for some vehicles where it is not required for vehicle function. The present invention achieves the above advantages of all wheel drive ground vehicles in a straightforward manner and permits the two sections to be quickly attached to one another.
The present invention provides a readily engagable or disengagable coupler and drive shaft for joining the two sections. This is achieved by providing a socket affixed to one of the sections and an entering member affixed to the other section that telescopically enters and is received and retained within the socket by uncomplicated mechanisms. Where articulation between the section is required, the connection between the entering member and the section to which it is attached is adapted to allow the requisite movement with respect to the roll axis and the yaw axis, and may also allow the transmission of drive power across the coupler.
The present invention also provides a joint between the two sections that can be rapidly engaged and disengaged on rough or irregular terrain rapidly by one operator. This is achieved by providing a coupler that is automatically aligned over a range of elevations and angles. For aligning the two members, a socket member with a relatively large mouth is adapted to receive the entering member. Inward at the mouth, the socket tapers to a relatively small cross sectional shape. The entry member is tapered correspondingly with a non-uniform taper which includes an aligning guide. Thus, precise initial positioning of the two parts of the joint is unnecessary because the two parts telescopically align automatically as the two sections are moved toward one another. The guide on the socket member, in cooperation with the taper of the entry member, allows the two parts to telescope into alignment automatically as the two sections are moved towards one another so that when the entry member is fully received in the socket, the two parts are precisely aligned and ready for final encouplement.
The insertion member includes a first cylindrical surface and a second cylindrical mating surface whose axis is parallel with the axis of said first surface. A tapered guideway is intermediate the first and second cylindrical surfaces. The socket member of the joint has corresponding first and second internal cylindrical surfaces. The socket member also includes an aligning guide which cooperates with the tapered guideway of the insertion member to automatically complete the alignment of insertion member into the socket.
A system of radial keys provides for final alignment of the coupler members and provides torsional load-carrying ability. A breechblock lock connected to the radial keys provides positive locking of the coupler members. This lock allows a single operator to rapidly and positively lock the coupler members together.
A power connection between the two sections is usually required so that all ground contact members can be powered. This is achieved in one form of the present invention by providing, as a part of the coupler, a drive shaft between the two sections of the coupler. This drive shaft is coupled by universal joints so as to avoid interference with articulation movement, and is coupled automatically when the coupler is fully engaged.